Method for forming ultra low k films using electron beam

ABSTRACT

The present invention generally provides a method for depositing a low dielectric constant film using an e-beam treatment. In one aspect, the method includes delivering a gas mixture comprising one or more organosilicon compounds and one or more hydrocarbon compounds having at least one cyclic group to a substrate surface at deposition conditions sufficient to deposit a non-cured film comprising the at least one cyclic group on the substrate surface. The method further includes substantially removing the at least one cyclic group from the non-cured film using an electron beam at curing conditions sufficient to provide a dielectric constant less than 2.5 and a hardness greater than 0.5 GPa.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/302,393, filed Nov. 22, 2002, now issued as U.S. Pat. No. 7,060,330,which claims benefit of U.S. provisional patent application Ser. No.60/378,799, filed May 8, 2002. Further, this application is related toU.S. patent application Ser. No. 10/302,375, filed Nov. 22, 2002, nowabandoned; U.S. patent application Ser. No. 10/428,374, filed May 1,2003, now issued as U.S. Pat. No. 6,936,551; U.S. patent applicationSer. No. 10/655,276, filed Sep. 3, 2003, now abandoned; U.S. patentapplication Ser. No. 10/773,060, filed Feb. 4, 2004, now issued as U.S.Pat. No. 7,056,560; U.S. patent application Ser. No. 10/783,748, filedFeb. 20, 2004, now issued as U.S. Pat. No. 7,323,399; U.S. patentapplication Ser. No. 10/824,313, filed Apr. 13, 2004, now abandoned;U.S. patent application Ser. No. 11/045,650, filed Jan. 28, 2005, nowissued as U.S. Pat. No. 7,256,139; co-pending U.S. patent applicationSer. No. 11/838,742, filed Aug. 14, 2007; and co-pending U.S. patentapplication Ser. No. 11/925,611, filed Oct. 26, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the fabrication of integrated circuits.More particularly, the invention relates to a method for depositingdielectric layers on a substrate and the structures formed by thedielectric layer.

2. Description of the Related Art

Semiconductor device geometries have dramatically decreased in sizesince such devices were first introduced several decades ago. Sincethen, integrated circuits have generally followed the two year/half-sizerule (often called Moore's Law), which means that the number of devicesthat will fit on a chip doubles every two years. Today's fabricationplants are routinely producing devices having 0.13 μm and even 0.1 μmfeature sizes, and tomorrow's plants soon will be producing deviceshaving even smaller geometries.

In order to further reduce the size of devices on integrated circuits,it has become necessary to use conductive materials having lowresistivity and to use insulators having low dielectric constants toreduce the capacitive coupling between adjacent metal lines. One suchlow k material is spin-on glass, such as un-doped silicon glass (USG) orfluorine-doped silicon glass (FSG), which can be deposited as a gap filllayer in a semiconductor manufacturing process. Other examples of low kmaterials include carbon doped silicon dioxide andpolytetrafluoroethylene. However, the continued reduction in devicegeometries has generated a demand for films having even lower k values.

Recent developments in low dielectric constants have focused onincorporating silicon, carbon, and oxygen atoms into the deposited film.One challenge in this area has been to develop a Si, C, and O containingfilm that has a low k value, but also exhibits desirable thermal andmechanical properties. Most often, films made of a Si, C, and O networkthat have a desirable dielectric constant exhibit poor mechanicalstrength and are easily damaged by etch chemistry and subsequent plasmaexposure, causing failure of the integrated circuit.

Therefore, there is a need for a process for making low dielectricconstant materials that would improve the speed and efficiency ofdevices on integrated circuits as well as the durability and mechanicalintegrity of the integrated circuit.

SUMMARY OF THE INVENTION

The present invention generally provides a method for depositing a lowdielectric constant film. In one aspect, the method includes deliveringa gas mixture comprising one or more organosilicon compounds and one ormore hydrocarbon compounds having at least one cyclic group to asubstrate surface at deposition conditions sufficient to deposit anon-cured film comprising the at least one cyclic group on the substratesurface and having a hardness less than about 0.3 GPa. The methodfurther includes substantially removing the at least one cyclic groupfrom the non-cured film using an electron beam at curing conditionssufficient to provide a dielectric constant less than 2.5 and a hardnessgreater than 0.5 GPa.

In another aspect, the method includes delivering a gas mixturecomprising one or more organosilicon compounds, one or more hydrocarboncompounds having at least one cyclic group, and two or more oxidizinggases to a substrate surface at deposition conditions sufficient todeposit a non-cured film comprising the at least one cyclic group on thesubstrate surface and having a hardness less than 0.3 GPa, andsubstantially removing the at least one cyclic group from the non-curedfilm using an electron beam at curing conditions sufficient to provide adielectric constant less than 2.2 and a hardness greater than 0.4 GPa.

In yet another aspect, the method includes delivering a gas mixturecomprising two or more organosilicon compounds, one or more hydrocarboncompounds having at least one cyclic group, and one or more oxidizinggases to a substrate surface at deposition conditions sufficient todeposit a non-cured film comprising the at least one cyclic group on thesubstrate surface, and substantially removing the at least one cyclicgroup from the non-cured film using an electron beam at curingconditions sufficient to provide a dielectric constant less than 2.5 anda hardness greater than 0.5 GPa, wherein the electron beam has a dosagegreater than about 200 micro coulombs per cm².

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a cross-sectional diagram of an exemplary CVD reactorconfigured for use according to embodiments described herein.

FIG. 2 is a flow chart of a hierarchical control structure of a computerprogram useful in conjunction with the exemplary CVD reactor of FIG. 1.

FIG. 3 is a cross sectional view showing a damascene structurecomprising a low dielectric constant film as described herein.

FIGS. 4A-4C are cross sectional views showing one embodiment of adamascene deposition sequence.

FIG. 5 is a cross sectional view showing a dual damascene structurecomprising two low dielectric constant films as described herein.

FIGS. 6A-6G are cross sectional views showing one embodiment of a dualdamascene deposition sequence.

FIG. 7 shows an exemplary integrated processing platform.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention includes a significant and unexpected reduction indielectric constants for films comprising silicon, oxygen, and carbon byblending one or more compounds having at least one cyclic group, one ormore organosilicon compounds, and optionally an oxidizing gas atconditions sufficient to form a pre-treated film network. In one aspect,one or more organic compounds having at least one cyclic group and oneor more organosilicon compounds are reacted with an oxidizing gas inamounts sufficient to deposit a low dielectric constant film on asemiconductor substrate.

The film may be deposited using plasma assistance within a processingchamber capable of performing chemical vapor deposition (CVD). Theplasma may be generated using pulse RF, high frequency RF, dualfrequency, dual phase RF, or any other known or yet to be discoveredplasma generation technique. Following deposition of the film, the filmis cured by electron beam to remove pendant organic groups, such ascyclic groups of the organic compounds that have been incorporated intothe film network during deposition.

The curing step supplies energy to the film network to volatize andremove at least a portion of the cyclic groups in the film network,leaving behind a more porous film network having a lower dielectricconstant. In most cases, the cured film demonstrates a hardness at leasttwo times, and as much as 600%, more than a non-cured film depositedaccording to embodiments described herein. Films cured using e-beam showan unexpected reduction in k value and an unexpected increase inhardness, not achievable with conventional curing techniques. Typically,the cured film has a dielectric constant of about 2.5 or less,preferably about 2.2 or less, and a hardness greater than about 0.6 GPa.

The term “organosilicon compound” as used herein is intended to refer tocompounds containing carbon atoms in organic groups, and can be cyclicor linear. Organic groups may include alkyl, alkenyl, cyclohexenyl, andaryl groups in addition to functional derivatives thereof. Preferably,the organosilicon compounds includes one or more carbon atoms attachedto a silicon atom whereby the carbon atoms are not readily removed byoxidation at suitable processing conditions. The organosilicon compoundsmay also preferably include one or more oxygen atoms. In one aspect, apreferred organosilicon compound has an oxygen to silicon atom ratio ofat least 1:1, and more preferably at least 2:1, such as about 4:1.

Suitable cyclic organosilicon compounds include a ring structure havingthree or more silicon atoms, and optionally one or more oxygen atoms.Commercially available cyclic organosilicon compounds include ringshaving alternating silicon and oxygen atoms with one or two alkyl groupsbonded to the silicon atoms. Some exemplary cyclic organosiliconcompounds include:

1,3,5-trisilano-2,4,6-trimethylene, —(—SiH₂CH₂—)₃— (cyclic) 2,4,6,8-—(—SiHCH₃—O—)₄— (cyclic) tetramethylcyclotetrasiloxane (TMCTS)octamethylcyclotetrasiloxane —(—Si(CH₃)₂—O—)₄— (cyclic) (OMCTS),2,4,6,8,10- —(—SiHCH₃—O—)₅— (cyclic) pentamethylcyclopentasiloxane,1,3,5,7-tetrasilano-2,6-dioxy-4,8- —(—SiH₂—CH₂—SiH₂—O—)₂— dimethylene,(cyclic) hexamethylcyclotrisiloxane —(—Si(CH₃)₂—O—)₃— (cyclic)

Suitable linear organosilicon compounds include aliphatic organosiliconcompounds having linear or branched structures with one or more siliconatoms and one or more carbon atoms. The organosilicon compounds mayfurther include one or more oxygen atoms. Some exemplary linearorganosilicon compounds include:

methylsilane, CH₃—SiH₃ dimethylsilane, (CH₃)₂—SiH₂ trimethylsilane,(CH₃)₃—SiH ethylsilane, CH₃—CH₂—SiH₃ disilanomethane, SiH₃—CH₂—SiH₃bis(methylsilano)methane, CH₃—SiH₂—CH₂—SiH₂—CH₃ 1,2-disilanoethane,SiH₃—CH₂—CH₂—SiH₃ 1,2-bis(methylsilano)ethane, CH₃—SiH₂—CH₂—CH₂—SiH₂—CH₃2,2-disilanopropane, SiH₃—C(CH₃)₂—SiH₃ diethoxymethylsilane (DEMS),CH₃—SiH—(O—CH₂—CH₃)₂ 1,3-dimethyldisiloxane, CH₃—SiH₂—O—SiH₂—CH₃1,1,3,3-tetramethyldisiloxane, (CH₃)₂—SiH—O—SiH—(CH₃)₂hexamethyldisiloxane (HMDS), (CH₃)₃—Si—O—Si—(CH₃)₃ 1,3-(SiH₃—CH₂—SiH₂—)₂—O bis(silanomethylene)disiloxane, bis(1-(CH₃—SiH₂—O—SiH₂—)₂—CH₂ methyldisiloxanyl)methane, 2,2-(CH₃—SiH₂—O—SiH₂—)₂—C(CH₃)₂ bis(1-methyldisiloxanyl)propane,hexamethoxydisiloxane (CH₃O)₃—Si—O—Si—(OCH₃)₃ (HMDOS)dimethyldimethoxysilane (CH₃O)₂—Si—(CH₃)₂ (DMDMOS)dimethoxymethylvinylsilane (CH₃O)₂—Si—(CH₃)—CH═CH₃ (DMMVS)

The term “cyclic group” as used herein is intended to refer to a ringstructure. The ring structure may contain as few as three atoms. Theatoms may include carbon, silicon, nitrogen, oxygen, fluorine, andcombinations thereof, for example. The cyclic group may include one ormore single bonds, double bonds, triple bonds, and any combinationthereof. For example, a cyclic group may include one or more aromatics,aryls, phenyls, cyclohexanes, cyclohexadienes, cycloheptadienes, andcombinations thereof. The cyclic group may also be bi-cyclic ortri-cyclic. Further, the cyclic group is preferably bonded to a linearor branched functional group. The linear or branched functional grouppreferably contains an alkyl or vinyl alkyl group and has between oneand twenty carbon atoms. The linear or branched functional group mayalso include oxygen atoms, such as a ketone, ether, and ester. Someexemplary compounds having at least one cyclic group includealpha-terpinene (ATP), vinylcyclohexane (VCH), and phenylacetate, justto name a few.

Suitable oxidizing gasses include oxygen (O₂), ozone (O₃), nitrous oxide(N₂O), carbon monoxide (CO), carbon dioxide (CO₂), water (H₂O),2,3-butane dione or combinations thereof. When ozone is used as anoxidizing gas, an ozone generator converts from 6% to 20%, typicallyabout 15%, by weight of the oxygen in a source gas to ozone, with theremainder typically being oxygen. However, the ozone concentration maybe increased or decreased based upon the amount of ozone desired and thetype of ozone generating equipment used. Disassociation of oxygen or theoxygen containing compounds may occur in a microwave chamber prior toentering the deposition chamber to reduce excessive dissociation of thesilicon containing compounds. Preferably, radio frequency (RF) power isapplied to the reaction zone to increase dissociation.

The e-beam treatment typically has a dose between about 50 and about2000 micro coulombs per square centimeter (μc/cm²) at about 1 to 20kiloelectron volts (KeV). The e-beam treatment is typically operated ata temperature between about room-temperature and about 450° C. for about1 such as about 2 minutes. Preferably, the e-beam treatment is performedat 400° C. for about 2 minutes. In one aspect, the e-beam treatmentconditions include 4.5 kV, 1.5 mA and 500 μc/cm² at 400° C. Although anye-beam device may be used, one exemplary device is the EBK chamber,available from Applied Materials, Inc.

The e-beam curing process improves mechanical strength of the depositedfilm network and also lowers the k-value. The energized e-beam altersthe chemical bonding in the molecular network of the deposited film andremoves at least a portion of the molecular groups from the film. Theremoval of the molecular groups creates voids or pores within the film,lowering the k value. The e-beam treatment also strengthens the filmnetwork by cross-linking Si—O—Si or Si—C—Si chains as inferred from FTIRspectroscopy.

Preferably, the deposited film has a carbon content between about 10 andabout 30 atomic percent, such as between about 10 and about 30 atomicpercent after curing. The carbon content of the deposited films refersto an elemental analysis of the film structure. The carbon content isrepresented by the percent of carbon atoms in the deposited film,excluding hydrogen atoms, which are difficult to quantify. For example,a film having an average of one silicon atom, one oxygen atom, onecarbon atom and two hydrogen atoms has a carbon content of 20 atomicpercent (one carbon atom per five total atoms), or a carbon content of33 atomic percent excluding hydrogen atoms (one carbon atom per threetotal atoms).

During deposition, the substrate is typically maintained at atemperature between about −20° C. and about 450° C. A power densityranging between about 0.03 W/cm² and about 3.2 W/cm², which is a RFpower level of between about 10 W and about 2000 W for a 200 mmsubstrate is typically used. Preferably, the RF power level is betweenabout 300 W and about 1700 W. The RF power is provided at a frequencybetween about 0.01 MHz and 300 MHz. The RF power may be cycled or pulsedto reduce heating of the substrate and promote greater porosity in thedeposited film. The RF power may also be continuous or discontinuous. Anexemplary processing chamber for depositing a low dielectric filmaccording to embodiments described herein is described below.

Exemplary CVD Reactor

FIG. 1 shows a vertical, cross-section view of a parallel plate chemicalvapor deposition processing chamber 10 having a high vacuum region 15.The processing chamber 10 contains a gas distribution manifold 11 havingperforated holes for dispersing process gases there-through to asubstrate (not shown). The substrate rests on a substrate support plateor susceptor 12. The susceptor 12 is mounted on a support stem 13 whichconnects the susceptor 12 to a lift motor 14. The lift motor 14 raisesand lowers the susceptor 12 between a processing postion and a lower,substrate-loading position so that the susceptor 12 (and the substratesupported on the upper surface of susceptor 12) can be controllablymoved between a lower loading/off-loading position and an upperprocessing position which is closely adjacent to the manifold 11. Whenthe susceptor 12 and the substrate are in the upper processing position,they are surrounded by an insulator 17.

During processing, gases introduced to the manifold 11 are uniformlydistributed radially across the surface of the substrate. A vacuum pump32 having a throttle valve controls the exhaust rate of gases from thechamber through a manifold 24. Deposition and carrier gases flow throughgas lines 18 into a mixing system 19 and then to the manifold 11.Generally, each process gas supply line 18 includes (i) safety shut-offvalves (not shown) that can be used to automatically or manually shutoff the flow of process gas into the chamber, and (ii) mass flowcontrollers (also not shown) to measure the flow of gas through the gassupply lines 18. When toxic gases are used in the process, severalsafety shut-off valves are positioned on each gas supply line 18 inconventional configurations.

The deposition process performed in the processing chamber 10 can beeither a thermal process or a plasma enhanced process. In a plasmaprocess, a controlled plasma is typically formed adjacent the substrateby RF energy applied to the gas distribution manifold 11 using a RFpower supply 25. Alternatively, RF power can be provided to thesusceptor 12 or RF power can be provided to different components atdifferent frequencies. The RF power supply 25 can supply either singleor mixed frequency RF power to enhance the decomposition of reactivespecies introduced into the high vacuum region 15. A mixed frequency RFpower supply typically supplies power at a high RF frequency (RF1) of13.56 MHz to the distribution manifold 11 and at a low RF frequency(RF2) of 360 KHz to the susceptor 12.

When additional dissociation of the oxidizing gas is desired, anoptional microwave chamber 28 can be used to input from between about 0Watts and about 6000 Watts to the oxidizing gas prior to the gasentering the processing chamber 10. The additional microwave power canavoid excessive dissociation of the organosilicon compounds prior toreaction with the oxidizing gas. A gas distribution plate (not shown)having separate passages for the organosilicon compound and theoxidizing gas is preferred when microwave power is added to theoxidizing gas.

Typically, any or all of the chamber lining, distribution manifold 11,susceptor 12, and various other reactor hardware is made out of materialsuch as aluminum or anodized aluminum. An example of such a CVD reactoris described in commonly assigned U.S. Pat. No. 5,000,113, entitled “AThermal CVD/PECVD Reactor and Use for Thermal Chemical Vapor Depositionof Silicon Dioxide and In-situ Multi-step Planarized Process”, issued toWang et al., which is incorporated by reference herein. The processingsystem 10 may be integrated into an integrated processing platform, suchas a Producer™ platform available from Applied Materials, Inc. Detailsof the Producer™ platform are described in commonly assigned U.S. Pat.No. 5,855,681, entitled “Ultra High Throughput Wafer Vacuum ProcessingSystem”, issued to Maydan et al., which is incorporated by referenceherein.

A system controller 34 controls the motor 14, the gas mixing system 19,and the RF power supply 25 which are connected therewith by controllines 36. The system controller 34 controls the activities of the CVDreactor and typically includes a hard disk drive, a floppy disk drive,and a card rack. The card rack contains a single board computer (SBC),analog and digital input/output boards, interface boards, and steppermotor controller boards. The system controller 34 conforms to the VersaModular Europeans (VME) standard which defines board, card cage, andconnector dimensions and types. The VME standard also defines the busstructure having a 16-bit data bus and 24-bit address bus.

FIG. 2 is a flow chart of a hierarchical control structure of a computerprogram product useful in conjunction with the exemplary CVD reactor ofFIG. 1. The system controller 34 operates under the control of acomputer program 410 stored on the hard disk drive 38. The computerprogram dictates the timing, mixture of gases, RF power levels,susceptor position, and other parameters of a particular process. Thecomputer program code can be written in any conventional computerreadable programming language such as, for example, 68000 assemblylanguage, C, C++, or Pascal. Suitable program code is entered into asingle file, or multiple files, using a conventional text editor, andstored or embodied in a computer usable medium, such as a memory systemof the computer. If the entered code text is in a high level language,the code is compiled, and the resultant compiler code is then linkedwith an object code of precompiled windows library routines. To executethe linked compiled object code, the system user invokes the objectcode, causing the computer system to load the code in memory, from whichthe CPU reads and executes the code to perform the tasks identified inthe program.

Still referring to FIG. 2, a user enters a process set number andprocess chamber number into a process selector subroutine 420 inresponse to menus or screens displayed on the CRT monitor by using thelight pen interface. The process sets are predetermined sets of processparameters necessary to carry out specified processes, and areidentified by predefined set numbers. The process selector subroutine420 (i) selects a desired process chamber on a cluster tool such as anCentura® platform (available from Applied Materials, Inc.), and (ii)selects a desired set of process parameters needed to operate theprocess chamber for performing the desired process. The processparameters for performing a specific process are provided to the user inthe form of a recipe and relate to process conditions such as, forexample, process gas composition, flow rates, temperature, pressure,plasma conditions such as RF bias power levels and magnetic field powerlevels, cooling gas pressure, and chamber wall temperature. Theparameters specified by the recipe are entered utilizing the lightpen/CRT monitor interface. The signals for monitoring the process areprovided by the analog input and digital input boards of the systemcontroller 34 and the signals for controlling the process are output tothe analog output and digital output boards of the system controller 34.

A process sequencer subroutine 430 comprises program code for acceptingthe identified process chamber and set of process parameters from theprocess selector subroutine 420, and for controlling operation of thevarious process chambers. Multiple users can enter process set numbersand process chamber numbers, or a user can enter multiple processchamber numbers, so the sequencer subroutine 430 operates to schedulethe selected processes in the desired sequence. Preferably the sequencersubroutine 430 includes computer readable program code to perform thesteps of (i) monitoring the operation of the process chambers todetermine if the chambers are being used, (ii) determining whatprocesses are being carried out in the chambers being used, and (iii)executing the desired process based on availability of a process chamberand type of process to be carried out. Conventional methods ofmonitoring the process chambers can be used, such as polling. Whenscheduling a process execute, the sequencer subroutine 430 can bedesigned to take into consideration the present condition of the processchamber being used in comparison with the desired process conditions fora selected process, or the “age” of each particular user enteredrequest, or any other relevant factor a system programmer desires toinclude for determining the scheduling priorities.

Once the sequencer subroutine 430 determines which process chamber andprocess set combination is going to be executed next, the sequencersubroutine 430 causes execution of the process set by passing theparticular process set parameters to a chamber manager subroutine 440which controls multiple processing tasks in a process chamber accordingto the process set determined by the sequencer subroutine 430. Forexample, the chamber manager subroutine 440 includes program code forcontrolling CVD process operations in the process chamber 10. Thechamber manager subroutine 440 also controls execution of variouschamber component subroutines which control operation of the chambercomponent necessary to carry out the selected process set. Examples ofchamber component subroutines are susceptor control subroutine 450,process gas control subroutine 460, pressure control subroutine 470,heater control subroutine 480, and plasma control subroutine 490. Thosehaving ordinary skill in the art would readily recognize that otherchamber control subroutines can be included depending on what processesare desired to be performed in a processing chamber.

In operation, the chamber manager subroutine 440 selectively schedulesor calls the process component subroutines in accordance with theparticular process set being executed. The chamber manager subroutine440 schedules the process component subroutines similarly to how thesequencer subroutine 430 schedules which process chamber and process setis to be executed next. Typically, the chamber manager subroutine 440includes steps of monitoring the various chamber components, determiningwhich components needs to be operated based on the process parametersfor the process set to be executed, and causing execution of a chambercomponent subroutine responsive to the monitoring and determining steps.

Operation of particular chamber component subroutines will now bedescribed with reference to FIG. 2. The susceptor control positioningsubroutine 450 comprises program code for controlling chamber componentsthat are used to load the substrate onto the susceptor 12, andoptionally to lift the substrate to a desired height in the processingchamber 10 to control the spacing between the substrate and the gasdistribution manifold 11. When a substrate is loaded into the processingchamber 10, the susceptor 12 is lowered to receive the substrate, andthereafter, the susceptor 12 is raised to the desired height in thechamber to maintain the substrate at a first distance or spacing fromthe gas distribution manifold 11 during the CVD process. In operation,the susceptor control subroutine 450 controls movement of the susceptor12 in response to process set parameters that are transferred from thechamber manager subroutine 440.

The process gas control subroutine 460 has program code for controllingprocess gas compositions and flow rates. The process gas controlsubroutine 460 controls the open/close position of the safety shut-offvalves, and also ramps up/down the mass flow controllers to obtain thedesired gas flow rate. The process gas control subroutine 460 is invokedby the chamber manager subroutine 440, as are all chamber componentssubroutines, and receives from the chamber manager subroutine processparameters related to the desired gas flow rates. Typically, the processgas control subroutine 460 operates by opening the gas supply lines, andrepeatedly (i) reading the necessary mass flow controllers, (ii)comparing the readings to the desired flow rates received from thechamber manager subroutine 440, and (iii) adjusting the flow rates ofthe gas supply lines as necessary. Furthermore, the process gas controlsubroutine 460 includes steps for monitoring the gas flow rates forunsafe rates, and activating the safety shut-off valves when an unsafecondition is detected.

In some processes, an inert gas such as helium or argon is put into theprocessing chamber 10 to stabilize the pressure in the chamber beforereactive process gases are introduced. For these processes, the processgas control subroutine 460 is programmed to include steps for flowingthe inert gas into the chamber 10 for an amount of time necessary tostabilize the pressure in the chamber, and then the steps describedabove would be carried out. Additionally, when a process gas is to bevaporized from a liquid precursor, the process gas control subroutine460 would be written to include steps for bubbling a delivery gas suchas helium through the liquid precursor in a bubbler assembly. For thistype of process, the process gas control subroutine 460 regulates theflow of the delivery gas, the pressure in the bubbler, and the bubblertemperature in order to obtain the desired process gas flow rates. Asdiscussed above, the desired process gas flow rates are transferred tothe process gas control subroutine 460 as process parameters.Furthermore, the process gas control subroutine 460 includes steps forobtaining the necessary delivery gas flow rate, bubbler pressure, andbubbler temperature for the desired process gas flow rate by accessing astored table containing the necessary values for a given process gasflow rate. Once the necessary values are obtained, the delivery gas flowrate, bubbler pressure and bubbler temperature are monitored, comparedto the necessary values and adjusted accordingly.

The pressure control subroutine 470 comprises program code forcontrolling the pressure in the processing chamber 10 by regulating thesize of the opening of the throttle valve in the exhaust pump 32. Thesize of the opening of the throttle valve is set to control the chamberpressure to the desired level in relation to the total process gas flow,size of the process chamber, and pumping set point pressure for theexhaust pump 32. When the pressure control subroutine 470 is invoked,the desired, or target pressure level is received as a parameter fromthe chamber manager subroutine 440. The pressure control subroutine 470operates to measure the pressure in the processing chamber 10 by readingone or more conventional pressure manometers connected to the chamber,compare the measure value(s) to the target pressure, obtain PID(proportional, integral, and differential) values from a stored pressuretable corresponding to the target pressure, and adjust the throttlevalve according to the PID values obtained from the pressure table.Alternatively, the pressure control subroutine 470 can be written toopen or close the throttle valve to a particular opening size toregulate the processing chamber 10 to the desired pressure.

The heater control subroutine 480 comprises program code for controllingthe temperature of the heat modules or radiated heat that is used toheat the susceptor 12. The heater control subroutine 480 is also invokedby the chamber manager subroutine 440 and receives a target, or setpoint, temperature parameter. The heater control subroutine 480 measuresthe temperature by measuring voltage output of a thermocouple located ina susceptor 12, compares the measured temperature to the set pointtemperature, and increases or decreases current applied to the heatmodule to obtain the set point temperature. The temperature is obtainedfrom the measured voltage by looking up the corresponding temperature ina stored conversion table, or by calculating the temperature using afourth order polynomial. The heater control subroutine 480 graduallycontrols a ramp up/down of current applied to the heat module. Thegradual ramp up/down increases the life and reliability of the heatmodule. Additionally, a built-in-fail-safe mode can be included todetect process safety compliance, and can shut down operation of theheat module if the processing chamber 10 is not properly set up.

The plasma control subroutine 490 comprises program code for setting theRF bias voltage power level applied to the process electrodes in theprocessing chamber 10, and optionally, to set the level of the magneticfield generated in the reactor. Similar to the previously describedchamber component subroutines, the plasma control subroutine 490 isinvoked by the chamber manager subroutine 440.

The pretreatment and method for forming a pretreated layer of thepresent invention is not limited to any specific apparatus or to anyspecific plasma excitation method. The above CVD system description ismainly for illustrative purposes, and other CVD equipment such aselectrode cyclotron resonance (ECR) plasma CVD devices,induction-coupled RF high density plasma CVD devices, or the like may beemployed. Additionally, variations of the above described system such asvariations in susceptor design, heater design, location of RF powerconnections and others are possible. For example, the substrate could besupported and heated by a resistively heated susceptor.

Deposition of a Low Dielectric Constant Film

FIG. 3 shows a damascene structure having a low dielectric constant filmof the present invention deposited thereon. The low dielectric constantfilm is deposited as a dielectric layer 314 on a dielectric liner orbarrier layer 312. A cap layer 316 is deposited on the dielectric layer314. The cap layer 316 acts as an etch stop during further substrateprocessing or alternatively, as a liner layer. The cap layer 316,dielectric layer 314, and dielectric liner or barrier layer 312 arepattern etched to define the openings of interconnects 317 such as linesthat expose underlying conducive features 310. A conductiveliner/barrier layer 318 is deposited within the interconnects 317, and aconductive material 320 is deposited thereon to fill the interconnects317. The substrate is typically planarized, as shown, after deposition.

FIGS. 4A-4C are cross sectional views of a substrate 300 having thesteps of the invention formed thereon. As shown in FIG. 4A, a dielectriclayer 314 of the low dielectric constant film is deposited on the lineror barrier layer 312 to a thickness between about 5,000 Å to about10,000 Å, depending on the size of the structure to be fabricated. Theliner or barrier layer 312 may be a silicon carbide layer, for example,from the PECVD of an alkylsilane compound using a plasma of an inertgas. The silicon carbide layer may be doped with oxygen or nitrogen. Theliner/barrier layer 312 may alternatively comprise another material,such as silicon nitride, which minimizes oxidation and/or diffusion ofconductive materials, such as copper, which may comprise conductivefeatures 310 previously formed in the substrate 300.

The cap layer 316, which can be a silicon carbide layer having a lowdielectric constant, is then deposited on the dielectric layer 314 byreaction of the trimethylsilane to a thickness of about 200 Å to about1000 Å using RF power in the range between about 10 and about 1000 wattsfor a 200 mm substrate. The silicon carbide material may be doped withoxygen or nitrogen.

As shown in FIG. 4B, the cap layer 316, the dielectric layer 314, andthe liner or barrier layer 312 are then pattern etched to define theinterconnects 317 and to expose the conductive feature 310 in substrate300. Preferably, the cap layer 316, the dielectric layer 314, and theliner or barrier layer 312 are pattern etched using conventionalphotolithography and etch processes for silicon carbide films. Any photoresist or other material used to pattern the cap layer 316 is removedusing an oxygen strip or other suitable process.

Following etching of the deposited material and removal of photo resistmaterials, exposed portions of the cap layer 316, the dielectric layer314, and the liner or barrier layer 312 may be treated with a reactivepre-clean process to remove contaminants, particulate matter, residues,and oxides that may have formed on the exposed portions of theinterconnects 317 and on the surface of the substrate. The reactivepre-clean process comprises exposing the substrate to a plasma,preferably comprising hydrogen, argon, helium, nitrogen, or mixturesthereof, at a power density between of 0.03 watts/cm² and about 3.2watts/cm², or at a power level between about 10 watts and 1000 for a 200millimeter substrate. The processing chamber is maintained at a pressureof about 20 Torr or less and at a substrate temperature of about 450° C.or less during the reactive clean process.

Referring to FIG. 4C, after the cap layer 316, the dielectric layer 314,and the liner or barrier layer 312 have been etched to define theinterconnects 317 and the photo resist has been removed, theinterconnects 317 are filled with a conductive material 320. Thestructure is preferably formed with a conductive material such asaluminum, copper, tungsten, or combinations thereof. Presently, thetrend is to use copper to form the smaller features due to the lowresistivity of copper (1.7 Ω-cm compared to 3.1 Ω-cm for aluminum).

Preferably, the conductive barrier layer 318 is first depositedconformably in the interconnects 317 to prevent copper migration intothe surrounding silicon and/or dielectric material. Barrier layersinclude titanium, titanium nitride, tantalum, tantalum nitride, andcombinations thereof among other conventional barrier layer materials.Thereafter, copper 320 is deposited using chemical vapor deposition,physical vapor deposition, electroplating, or combinations thereof, toform the conductive structure. Once the structure has been filled withcopper or other conductive material, the surface is planarized usingchemical mechanical polishing to produce the finished damascenestructure shown in FIG. 3.

FIG. 5 shows a dual damascene structure which includes two lowdielectric constant films and two silicon carbide cap layers or dopedsilicon carbide cap layers deposited thereon. A conductive feature 502is formed in a substrate 500. The first low dielectric constant film isdeposited as a first dielectric layer 510 on a liner or barrier layer512, for example, silicon carbide. A first silicon carbide cap layer 514is deposited on the first dielectric layer 510. The silicon carbide caplayer 514 reduces the dielectric constant of the low dielectric constantfilm and is pattern etched to define the openings of verticalinterconnects such as contacts/vias. For the dual damascene application,a second dielectric layer 518 comprising the second low dielectricconstant film is deposited over the patterned silicon carbide cap layer514. The second silicon carbide cap layer 519 is deposited on the seconddielectric layer 518 and pattern etched to define horizontalinterconnects such as lines. An etch process is performed to define thehorizontal interconnects down to the first silicon carbide layer 314which functions as an etch stop, and to define the verticalinterconnects and expose the conductive feature 502 in substrate 500prior to filling the interconnects with a conductive material 526.

A preferred method for making the dual damascene structure shown in FIG.5 is sequentially depicted in FIGS. 6A-6G, which are cross sectionalviews of a substrate having the steps of the invention formed thereon.As shown in FIG. 6A, an initial first dielectric layer 510 of the lowdielectric constant film is deposited on the liner or barrier layer 512to a thickness between about 5,000 Å and about 10,000 Å, depending onthe size of the structure to be fabricated. The liner layer 512 may be asilicon carbide layer, which may be doped with oxygen or nitrogen. Theliner/barrier layer 512 may alternatively comprise another material,such as silicon nitride, which minimizes oxidation and/or diffusion ofconductive materials, such as copper, which may comprise conductivefeatures 502 previously formed in the substrate 500.

As shown in FIG. 6B, the first cap layer 514, which includes a siliconcarbide layer or doped silicon carbide layer is then deposited on thefirst dielectric layer to a thickness between about 200 and about 1000 Åusing RF power in the range between about 10 and about 1000 watts for a200 mm substrate. The first cap layer 514 is then pattern etched todefine the contact/via openings 516 and to expose first dielectric layer510 in the areas where the contacts/vias are to be formed as shown inFIG. 6C. Preferably, the first cap layer 514 is pattern etched usingconventional photolithography and etch processes for silicon carbidefilms.

After the first cap layer 514 has been etched to pattern thecontacts/vias 516 and the photo resist has been removed, a seconddielectric layer 518 is deposited over the first cap layer 514 to athickness between about 5,000 Å and about 10,000 Å as described for thefirst dielectric layer 510 as shown in FIG. 6D.

A second cap layer 519, which includes a silicon carbide layer or dopedsilicon carbide layer is then deposited on the second dielectric layer518 to a thickness of about 200 to about 1000 Å. The silicon carbidematerial may be doped with oxygen or nitrogen. The second cap layer 519is then patterned to define lines 520, as shown in FIG. 6E. The lines520 and contacts/vias 516 are then etched using reactive ion etching orother anisotropic etching techniques to define the metallizationstructure (i.e., the openings for the lines and contact/via) and exposethe conductive feature 502 as shown in FIG. 6F. Any photo resist orother material used to pattern and etch the second cap layer 519 isremoved using an oxygen strip or other suitable process.

Following etching of the deposited material and removal of photo resistmaterials, exposed portions of the second cap layer 519, the seconddielectric layer 518, the first cap layer 514, the first dielectriclayer 510, and the liner or barrier layer 512 may be treated with areactive pre-clean process, as described above, to remove contaminants,particulate matter, residues, and oxides that may have formed on theexposed portions of the contact/via openings 516, the line openings 520,and the conductive feature 502.

The metallization structure is then formed with a conductive materialsuch as aluminum, copper, tungsten or combinations thereof. Presently,the trend is to use copper to form the smaller features due to the lowresistivity of copper (1.7 Ω-cm compared to 5.1 Ω-cm for aluminum).Preferably, as shown in FIG. 6G, a conductive barrier layer 524 is firstdeposited conformably in the metallization pattern to prevent coppermigration into the surrounding silicon and/or dielectric material.Barrier layers include titanium, titanium nitride, tantalum, tantalumnitride, and combinations thereof among other conventional barrier layermaterials. Thereafter, copper 526 is deposited using either chemicalvapor deposition, physical vapor deposition, electroplating, orcombinations thereof to form the conductive structure. Once thestructure has been filled with copper or other metal, the surface isplanarized using chemical mechanical polishing as shown in FIG. 5.

These processing steps are preferably integrated on a processingplatform to avoid interim contamination of the substrate. One exemplaryintegrated processing tool is an ENDURA platform available from AppliedMaterials, Inc. of Santa Clara, Calif. FIG. 7 shows a schematic planview of an exemplary multi-chamber processing system 700, such as theENDURA platform. A similar multi-chamber processing system is disclosedin U.S. Pat. No. 5,186,718, entitled “Stage Vacuum Wafer ProcessingSystem and Method,” issued on Feb. 16, 1993, which is incorporated byreference herein.

The system 700 generally includes load lock chambers 702, 704 for thetransfer of substrates into and out from the system 700. Since thesystem 700 is typically under vacuum, the load lock chambers 702, 704may “pump down” the substrates introduced into the system 700. A firstrobot 710 may transfer the substrates between the load lock chambers702, 704, and a first set of one or more substrate processing chambers712, 714, 716, 718 (four are shown). Each processing chamber 712, 714,716, 718, can be outfitted to perform a number of substrate processingoperations such as cyclical layer deposition, chemical vapor deposition(CVD), physical vapor deposition (PVD), etch, pre-clean, degas,orientation and other substrate processes. The first robot 710 alsotransfers substrates to and from one or more transfer chambers 722, 724.

The transfer chambers 722, 724, are used to maintain ultrahigh vacuumconditions while allowing substrates to be transferred within the system700. A second robot 730 may transfer the substrates between the transferchambers 722, 724 and a second set of one or more processing chambers732, 734, 736, 738. Similar to processing chambers 712, 714, 716, 718,the processing chambers 732, 734, 736, 738 can be outfitted to perform avariety of substrate processing operations, such as cyclical deposition,chemical vapor deposition (CVD), physical vapor deposition (PVD), etch,pre-clean, degas, and orientation, for example. Any of the substrateprocessing chambers 712, 714, 716, 718, 732, 734, 736, 738 may beremoved from the system 700 if not necessary for a particular process tobe performed by the system 700.

In one arrangement, each processing chamber 732 and 738 may be acyclical deposition chamber adapted to deposit a nucleation layer; eachprocessing chamber 734 and 736 may be a cyclical deposition chamber, achemical vapor deposition chamber, or a physical vapor depositionchamber adapted to form a bulk fill deposition layer; each processingchamber 712 and 714 may be a chemical vapor deposition chamber, or acyclical deposition chamber adapted to deposit a dielectric layer asdescribed herein; and each processing chamber 716 and 718 may be an etchchamber outfitted to etch apertures or openings for interconnectfeatures. This one particular arrangement of the system 700 is providedto illustrate the invention and should not be used to limit the scope ofthe invention.

The following examples illustrate the low dielectric films of thepresent invention. The films were deposited on 200 mm substrates using achemical vapor deposition chamber, such as the “Producer DxZ” system,available from Applied Materials, Inc. of Santa Clara, Calif.

EXAMPLE 1

A low dielectric constant film was deposited on each of three 200 mmsubstrates at about 8 Torr and temperature of about 200° C. Thefollowing processing gases and flow rates were used:

-   -   Alpha-terpinene (ATP), at 3,000 mgm;    -   Diethoxymethylsilane (DEMS), at 800 mgm; and    -   Carbon dioxide, at 1,000 sccm.

Each substrate was positioned 300 mils from the gas distributionshowerhead. A power level of 600 W at a frequency of 13.56 MHz wasapplied to the showerhead for plasma enhanced deposition of the films.Each films was deposited at a rate of about 1,000 Å/min, and had adielectric constant (k) of about 4.0 measured using a SSM 5100 Hg CVmeasurement tool at 0.1 MHz. Each film also exhibited a hardness ofabout 0.1 GPa.

Thermal Anneal:

The first deposited film was subjected to a thermal anneal process. Theanneal treatment utilized a temperature of about 425° C. at a pressureof about 10 Torr in an inert gas environment for about 4 hours. Shorteranneal times resulted in higher k values. The thermally annealed filmhad a lowest k value of about 2.1 and a hardness of about 0.2 GPa.

E-Beam @ 400° C.:

The second deposited film was subjected to a high temperature electronbeam (e-beam) treatment using a dose of about 300 μc/cm², at about 4.5KeV and 1.5 mA, and at about 400° C. The e-beam treatment lasted forabout 2 minutes. Following the e-beam treatment, the film exhibited adielectric constant of about 2.1 which is about 60% less than thenon-cured films and similar to the lowest value of the thermallyannealed film. The e-beam film also exhibited a hardness of about 0.7GPa, which is about an 600% increase compared to the non-cured films,and a 250% increase compared to the thermally annealed film.

E-Beam at Room Temperature:

The third deposited film was subjected to a low temperature electronbeam (e-beam) treatment using a dose of about 300 μc/cm², at about 4.5KeV and 1.5 mA, and at about 35° C. The e-beam treatment lasted forabout 2 minutes. Following the e-beam treatment, the film exhibited adielectric constant of about 2.3 which is about 57% less than thenon-cured films. The e-beam film also exhibited a hardness of about 0.5GPa, which is about an 400% increase compared to the non-cured films,and a 150% increase compared to the thermally annealed film.

EXAMPLE 2

A low dielectric constant film was deposited on each of three substratesat about 8 Torr and temperature of about 225° C. The followingprocessing gases and flow rates were used:

-   -   Alpha-terpinene (ATP), at 3,000 mgm;    -   Diethoxymethylsilane (DEMS), at 800 mgm;    -   Carbon dioxide, at 1,500 sccm; and    -   Oxygen, at 100 sccm.

Each substrate was positioned 300 mils from the gas distributionshowerhead. A power level of 600 W at a frequency of 13.56 MHz wasapplied to the showerhead for plasma enhanced deposition of the films.Each film was deposited at a rate of about 1,800 A/min, and had adielectric constant (k) of about 2.85 measured using SSM 5100 Hg CVmeasurement tool at 0.1 MHz. Each film also exhibited a hardness ofabout 0.23 GPa.

Thermal Anneal:

The first deposited film was subjected to a thermal anneal process. Theanneal treatment utilized a temperature of about 450° C. at a pressureof about 10 Torr in an inert gas environment for about 30 minutes.Shorter anneal times resulted in higher k values. The thermally annealedfilm had a refractory index (RI) of about 1.29, a lowest k value ofabout 2.08, and a hardness of about 0.23 GPa.

E-Beam @ 400° C. and 200 μc/cm²:

The second deposited film was subjected to a high temperature electronbeam (e-beam) treatment using a dose of about 200 μc/cm², at about 4.5KeV and 1.5 mA, and at about 400° C. The e-beam treatment lasted forabout 100 seconds. Following the e-beam treatment, the film exhibited adielectric constant of about 2.07 which is about 27% less than thenon-cured films and similar to the lowest value of the thermallyannealed film. The e-beam film also exhibited a hardness of about 0.42GPa, which is about an 80% increase compared to the non-cured films andthe thermally annealed film.

E-Beam @ 400° C. and 500 μc/cm²:

The third deposited film was subjected to a low temperature electronbeam (e-beam) treatment using a dose of about 500 μc/cm², at about 4.5KeV and 1.5 mA, and at about 35° C. The e-beam treatment lasted forabout 250 seconds. Following the e-beam treatment, the film exhibited adielectric constant of about 2.14 which is about 25% less than thenon-cured films. The e-beam film also exhibited a hardness of about 0.74GPa, which is about a 220% increase compared to the non-cured films andthe thermally annealed film.

EXAMPLE 3

A low dielectric constant film was deposited on each of two substratesat about 8 Torr and a temperature of about 225° C. The followingprocessing gases and flow rates were used:

-   -   Alpha-terpinene (ATP), at 4,000 mgm;    -   Octamethylcyclotetrasiloxane (OMCTS), at 200 mgm;    -   Oxygen, at 200 sccm; and    -   Carbon dioxide 2,000 sccm.

Each substrate was positioned about 300 mils from the gas distributionshowerhead. A power level of 500 W at a frequency of 13.56 MHz wasapplied o the the showerhead for plasma enhanced deposition of thefilms. Each film was deposited at a rate of about 1,000 ÅA/min, and hada dielectric constant (k) of about 4.0 measured using a SSM 5100 Hg CVmeasurement tool at 0.1 MHz. Each film also exhibited a hardness ofabout 0.1 GPa.

E-Beam @ 400° C. and 120 μc/cm²:

The first deposited film was subjected to a high temperature electronbeam (e-beam) treatment using a dose of about 120 μc/cm², at about 4.5KeV and 1.5 mA, and at about 400° C. The e-beam treatment lasted forabout 30 seconds. Following the e-beam treatment, the film exhibted adielectric constant of about 1.9 which is about 52% less than thenon-cured films . The e-beam film also exhibited a hardness of about 0.5GPa, which is about a 400% increase compared to the to the non-curedfilms.

E-Beam @ 400° C. and 600 μc/cm²:

The second deposited film was subjected to a low temperature electronbeam (e-beam) treatment using a dose of about 600 μc/cm², at about 4.5KeV and 1.5 mA, and at about 400° C. The e-beam treatment lasted forabout 150 seconds. Following the e-beam treatment, the film exhibited adielectric constant of about 2.2, which is about 45% less than thenon-cured films. The e-beam film also exhibted a a hardness of about 0.8GPa, which is about a 700% increase compared to the non-cured films.

EXAMPLE 4

A low dielectric constant film was deposited on a substrate at about 8Torr and a temperature of about 225° C. The following processing gasesand flow rates were used:

-   -   ATP, at 3,000 mgm;    -   TMS, at 500 sccm;    -   DEMS, at 600 mgm;    -   Oxygen, at 100 sccm; and    -   Carbon dioxide, at 1,500 sccm.

The substrate was positioned about 300 mils from the gas distributionshowerhead. A power level of 600 W at a frequency of 13.56 MHz wasapplied o the showerhead for plasma enhanced deposition of the films.The film was deposited at a rate of about 2,000 Å/min, and had adielectric constant (k) of about 4.3 measured using a SSM 5100 Hg CVmeasurement tool at 0.1 MHz. The film also exhibited a hardness of about0.1 GPa.

E-Beam @ 400° C. and 200 μc/cm ₂ :

The deposited film was subjected to a high temperature electron beam(e-beam) treatment using a dose of about 200 μc/cm2, at about 4.5 KeVand 1.5 mA, and at about 400° C. The e-beam treatment lasted for about30 seconds. Following the e-beam treatment, the film exhibited adielectric constant of about 2.2 which is about 50% less than thenon-cured film. The e-beam film also exhibited a hardness of about 0.7GPa, which is about a 600% increase compared to the non-cured film.

EXAMPLE 5

A low dielectric constant film was deposited on a substrate at about 8Torr and a temperature of about 225° C. The following processing gasesand flow rates were used:

-   -   ATP, at 4,000 mgm;    -   TMS, at 1,000 sccm;    -   OMCTS, at 200 mgm    -   Oxygen, at 100 sccm; and    -   Carbon dioxide, at 1,500 sccm.

The substrate was positioned about 300 mils from the gas distributionshowerhead. A power level of 500 W at a frequency of 13.56 MHz wasapplied o the showerhead for plasma enhanced deposition of the films.The film was deposited at a rate of about 1,600 Å/min, and had adielectric constant (k) 4.5 measured a using SSM 5100 Hg CV measurementtool at 0.1 MHz. The film also exhibited a hardness of about 0.1 GPa.

E-BEAM @ 400° C. and 200 μc/cm ²:

The deposited film was subjected to a high temperature electron beam(e-beam) treatment using a dose of about 200 μc/cm₂, at about 4.5 KeVand 1.5 mA, and at about 400° C. The e-beam treatment lasted for about30 seconds. Following the e-beam treatment, the film exhibited adielectric constant of about 2.3 which is about 50% less than thenon-cured film. The e-beam film also exhibited a hardness of about 0.7GPa, which is about a 600% increase compared to the non-cured film.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A method for depositing a dielectric film, comprising: reacting a gasmixture comprising one or more organosilicon compounds and one or morehydrocarbon compounds having at least one cyclic group at conditionssufficient to deposit a film comprising the at least one cyclic group ona substrate, wherein the one or more hydrocarbon compounds comprisesalpha-terpinene; and substantially removing the at least one cyclicgroup from the film using an electron beam.
 2. The method of claim 1,wherein the electron beam forms pores in the film.
 3. The method ofclaim 1, wherein the one or more organosilicon compounds comprisesoctamethylcyclotetrasiloxane (OMCTS).
 4. The method of claim 1, whereinthe one or more organosilicon compounds comprises diethoxymethylsilane(DEMS).
 5. The method of claim 1, wherein the one or more organosiliconcompounds is selected from the group consisting of1,3,5-trisilano-2,4,6-trimethylene,1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS),octamethylcyclotetrasiloxane (OMCTS),1,3,5,7,9-pentamethylcyclopentasiloxane,1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene,hexamethylcyclotrisiloxane, methylsilane, dimethylsilane,trimethylsilane, ethylsilane, disilanomethane, bis(methylsilano)methane,1,2-disilanoethane, 1,2-(methylsilano)ethane, 2,2-disilanopropane,diethoxymethylsilane (DEMS), 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane (HMDS),1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)propane,hexamethoxydisiloxane (HMDOS), dimethyldimethoxysilane (DMDMOS), anddimethoxymethylvinylsilane (DMMVS).
 6. The method of claim 1, whereinthe deposited film has between about 10 and about 30 atomic percentcarbon after being treated with the electron beam.
 7. The method ofclaim 1, wherein the electron beam is used at curing conditionssufficient to lower the dielectric constant of the film.
 8. A method fordepositing a dielectric film, comprising: reacting a gas mixturecomprising one or more organosilicon compounds, one or more hydrocarboncompounds having at least one cyclic group, and one or more oxidizinggases at conditions sufficient to deposit a film comprising the at leastone cyclic group on a substrate, wherein the one or more hydrocarboncompounds comprises alpha-terpinene; and substantially removing the atleast one cyclic group from the film using an electron beam.
 9. Themethod of claim 8, wherein the one or more oxidizing gases are selectedfrom the group consisting of oxygen, carbon dioxide, 2,3-butanedione,ozone, carbon monoxide, water, nitrous oxide, and combinations thereof.10. The method of claim 8, wherein the one or more oxidizing gases areselected from the group consisting of oxygen, 2,3-butanedione, ozone,carbon monoxide, water, nitrous oxide, and combinations thereof.
 11. Themethod of claim 8, wherein the one or more oxidizing gases is oxygen.12. The method of claim 11, wherein the one or more organosiliconcompounds comprises diethoxymethylsilane (DEMS).
 13. The method of claim12, wherein the one or more organosilicon compounds further comprisestrimethylsilane.
 14. The method of claim 11, wherein the one or moreorganosilicon compounds comprises octamethylcyclotetrasiloxane (OMCTS).15. The method of claim 8, wherein the deposited film has between about10 and about 30 atomic percent carbon after being treated with theelectron beam.